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Re: The Naked Atari 800
Posted: 20 Dec 2025 11:44
by rubber_jonnie
Well, 3.546894Mhz crystals are very much unobtanium it seems, I've searched all over RS, Farnell, Digi-Key and Mouser.
Closest to 3.546894 Mhz I could find was 3.5Mhz, and not sure that would be good enough. Also, shipping for a part that costs pennies is ridiculous.
I did manage to find some on eBay being sold by the brewing academy, but at $9 per crystal and nearly $23 shipping I'm not going to be buying those.
I think perhaps I can borrow one from a 2600Jr as I have a couple of those I don't really need too much since I have a 2600+/7800+ and a light sixer.
Time to go and have a look round my workshop.
Re: The Naked Atari 800
Posted: 20 Dec 2025 13:30
by PhilC
rubber_jonnie wrote: 20 Dec 2025 11:44
Well, 3.546894Mhz crystals are very much unobtanium it seems, I've searched all over RS, Farnell, Digi-Key and Mouser.
Closest to 3.546894 Mhz I could find was 3.5Mhz, and not sure that would be good enough. Also, shipping for a part that costs pennies is ridiculous.
I did manage to find some on eBay being sold by the brewing academy, but at $9 per crystal and nearly $23 shipping I'm not going to be buying those.
I think perhaps I can borrow one from a 2600Jr as I have a couple of those I don't really need too much since I have a 2600+/7800+ and a light sixer.
Time to go and have a look round my workshop.
Might have one of those too, will look later on.
Re: The Naked Atari 800
Posted: 20 Dec 2025 14:07
by olivier.jan
Let me be a bit stubborn, it seem 14.187576 crystals are more available (
https://rudedogretros.co.uk/product/ata ... 187576mhz/) and will do the job once divided by 4 ;-)
Re: The Naked Atari 800
Posted: 20 Dec 2025 14:33
by rubber_jonnie
I do actually already have one from an XE to which has been upgraded to VBXE, but have just stolen the correct one from a 2600JR so no massive rush now.
I have another annoying issue I need to fix that's higher priority...
I just managed to damage the SD card in my A500 RGB2HDMI and I need to replace it.
:dizzy:
Re: The Naked Atari 800
Posted: 20 Dec 2025 16:31
by rubber_jonnie
OK, so I fixed the A500 RGB2HDMI SD card. Or rather I threw it in the bin and replaced it as I'd managed to crack it down the middle.
So, behind a bit because of that, but I did dig this out:
IMG20251220162000.jpg
Will have a look and see what I need to build a circuit with a clock divider and will see how I get on.
Re: The Naked Atari 800
Posted: 20 Dec 2025 22:57
by olivier.jan
74LS/HCT/ACT/161 or 163 will do. I’ve been using 74HCT163 in a small 6502 based SBC I built a few years back: run the CPU at 14.187576 and get a proper 3.546894 frequency for the video.
Re: The Naked Atari 800
Posted: 21 Dec 2025 10:44
by rubber_jonnie
olivier.jan wrote: 20 Dec 2025 22:57
74LS/HCT/ACT/161 or 163 will do. I’ve been using 74HCT163 in a small 6502 based SBC I built a few years back: run the CPU at 14.187576 and get a proper 3.546894 frequency for the video.
Thanks.
I seem to be Mr Clumsy at the moment, aside from breaking the SD card in my A500 RGB2HDMI I spilled a drink on my Macbook last night and now no keyboard so reverting to Windows while I see if I can fix it...
On the plus side I'm down to the keyboard, it's quite simple to disassemble, on the negative side I have no idea how to get the keyboard out now I'm here.
So the 800 is parked for now...
Re: The Naked Atari 800
Posted: 21 Dec 2025 11:33
by stephen_usher
Oh! Hopefully not one of the riveted in keyboards!
Re: The Naked Atari 800
Posted: 21 Dec 2025 11:52
by rubber_jonnie
stephen_usher wrote: 21 Dec 2025 11:33
Oh! Hopefully not one of the riveted in keyboards!
It is riveted in...
Also screwed in, which makes no sense at all.
So since everything else works, I took out the guts and I'm flushing the keyboard through with IPA, it's all I can do for now as I'm not ripping out the old keyboard until I have a replacement, which I don't even know if I can get.
Re: The Naked Atari 800
Posted: 21 Dec 2025 11:53
by stephen_usher
:crossed1: